1. Field of the Invention
A tape cassette, in particular a magnetic tape cassette, having one or more tape rolls on an essentially flangeless hub, onto which and/or from which a tape can be wound or unwound in a cassette housing, support liners having curved or bent liner regions which are coordinated with one another, are opposite one another with respect to the central cassette plane and can come into contact with the hubs, the tape rolls and the tape temporarily or permanently being provided between the tape roll having tape windings and the bottom and lid walls of the cassette, and an axial bearing constriction being provided between the hubs and the cassette housing, and the support liners extending at least as far as the bearing constriction, and suitable support liners for such tape cassettes.
2. Description of the Related Art
German Utility Model 8,606,119 discloses a tape cassette whose housing is provided with annular beads in the region outside the hubs. Although support liners which are likewise bent are used, even minor disturbances of the tape roll (unevenness) result in Jamming, thus preventing operation of the cassette.
With the cassette according to German Published Application DAS 2,327,828, a certain axial bearing resilience is achievable for the tape roll by virtue of the fact that inner rings projecting beyond the normal end face of the hubs are supported on resilient liner parts located above corresponding housing cavities. However, this provides virtually no guidance for the tape roll, so that tape roll and running problems are not avoided.
German Utility Model 7,221,230 furthermore describes, as bearing means for hubs in magnetic tape cassettes, support liners which are located opposite one another, have embossed circular rings and are arranged coaxially over the hubs but contribute essentially nothing to tape roll and tape guidance.
Finally, German Patent 2,825,457 combined two of the abovementioned possibilities, the use of a raised bearing edge on the hub and of longitudinal embossings in the liner which engage the annular groove in conventional hubs, in conjunction with liner regions which are supported on the housing walls outside the hub diameter. The disadvantage here is the tape clip present on conventional hubs, which leads to irregularities in the rotation of the hub, which should in fact be better guided by the bearing edge and the liner embossings.
Dimensioning the hubs and liner embossings is difficult if it is intended to avoid jamming of the tape roll in all operating states. This situation cannot be altered also because a relatively broad liner middle part which is convex with respect to the housing inner walls and is intended to provide additional resilient support for the hubs is provided between the liner embossings. Such broad liner middle part deformations are also very stable here, cannot be produced accurately and repeatably in large amounts, are caused to disappear by thermoplastic flow or shrinkage or lose their curvature through adhesion due to elastic loading on the housing walls and hence lose their effectiveness. Thus, tape rolls which are step-like and wound in other irregular ways can still form and lead to the known problems with cassette operation.
It is an object of the present invention better to hold, align and guide the hub, the tape roll and the tape and to provide tape cassettes suitable for this purpose or suitable support liners for such tape cassettes.